Conventionally, the luminance level for light devices can be controlled by dimmers. Corresponding to different requirements, different kinds of dimmers can be applied. The dimmers can be, for example, Triac, voltage level control, wireless, PWM control.
However, in order to meet requirements for different clients, the manufacturers need to respectively prepare a large number of lighting devices with different kinds of dimmers. Therefore, the storage cost and manufacturing cost are greatly increased.